This magnificent building is the Rheinfels Castle overlooking St Goar
And just across the otherside of the river is the Katz Castle
It wasn't all castle - the trains are a constant in this part of the world, as are the barges, and the image of them appearing from the hillside is a contrast to the castles above.
The Pfalzgrafenstein Castle by Kaub was originally built by King Ludwig to collect tolls on the river.
And this could be the Rheinstein Castle.